16 Pa. Stat. § 5771
The county commissioners may locate, lay out, open, construct and maintain public bridges across any river or stream, whether such bridge is wholly or partly within any city, borough or township therein, together with such bridge approaches, viaduct or other approaches as the county commissioners may deem necessary or convenient for the purpose of connecting any such bridge with the existing streets or public roads in such cities, boroughs or townships, and to that end may take, enter upon, appropriate property and rights of property of all kinds, whether devoted to a public or private use, for the purposes aforesaid, and for the necessary slopes, piers, walls, abutments, fills and embankments, in the manner and subject to the restrictions and procedure provided in Article XXVI of this act, and may enter upon or over any street, public highway or public road in such cities, boroughs or townships.
16 P.S. § 5771